Since the existing routing algorithms for power communication network could not be used for finding a pair of routes, the maximally disjoint routing algorithm under the most reliable loop strategy (MRMLS) is proposed. Three types of double routing algorithms for the public communication network are discussed. Considering the diversity of the network topology, the maximally disjoint routing algorithm is adopted. The reliability of maximally disjoint routes is studied, and the maximally disjoint routes with the characteristic of the most reliable loop are put to use. The original maximally disjoint routing algorithm is improved, and the reliability of nodes and links is considered in the proposed algorithm. Simulation experiment compares MRMLS with another two available routing algorithms. The experiment results show the feasibility and validity of MRMLS.